Chlorofluorocarbon compounds (hereinafter referred simply as CFCs) have little toxicity and are, in many cases, non-flammable and chemically stable. Various CFCs having different boiling points are available. By virtue of such properties, 1,1,2-trichloro-1,2,2-trifluoroethane (R113) is used as a solvent or a blowing agent; trichloromonofluoromethane (R11) is used as a blowing agent or a propellant; and dichlorodifluoromethane (R12) is used as a propellant or a refrigerant.
Chemically stable R11, R12 and R113 have long lifetime in the troposphere and reach the stratosphere, where they will be dissociated by solar radiation to release chlorine radicals, which initiate a chain reaction with ozone and deplete the ozone layer. Accordingly, the regulations for limiting the use of such conventional CFCs have been implemented. Therefore, a research has been actively conducted to develop a CFC alternative which scarcely depletes the ozone layer.